1. Field of the Invention
This invention relates to a portable vertical boring machine and, more specifically, to such a machine which is capable of boring and/or facing a circular region of large circular components or other work pieces which have central axis which are disposed vertically during the boring and/or facing process. The preferred machine is portable and capable of being transported to various locations for on-site boring and/or facing of various circular components or work pieces.
2. Description of the Prior Art
The preferred portable vertical boring machine is configured to bore and/or face large circular regions of various work pieces such as large turbine diaphragm rings or the like which typically have inside diameters ranging between 22 inches and 140 inches. Because of the large size of such components, it is not uncommon for the boring and/or facing process to be performed on large machines permanently installed at remote locations. Consequently, when a large turbine or the like must be overhauled, many major components must be disassembled and shipped to the remote location for being reworked prior to reassembly. Typically, such large boring and/or facing machines located at remote locations are configured to include a centrally disposed boring or facing component with a large rotating support table to which the circular component or work piece is attached. Accordingly, the relative circular movement between the boring and/or facing tool and the work piece is produced by rotating the support table about the relatively "fixed" tool supporting component. The means for driving the support table for such large circular components or work pieces are relatively complicated and must include means for accurately locating the circular component or work piece thereon in order to insure accurate boring and/or facing of the surfaces thereof. With these large machines including secure means for maintaining the "fixed" tool supporting component relative to the support table, the overall configuration prevents them from being moved from their permanent locations to perform any on-site boring and/or facing of the work pieces.
Consequently, although such machines work quite satisfactorily and provide accurate boring and/or facing of large circular components or work pieces, the overall process and procedure is considered relatively expensive because of the extensive down time of the turbine or the like during overhaul and the cost of shipping the various large work pieces to such remote locations.
As a result, there have also been utilized a number of portable boring bars which can be brought to the site for boring the work pieces. Such portable boring bars tend to be mounted horizontally or vertically through various means to generally provide for the boring of such large circular components or work pieces as they are "mounted" within the turbine housing or the like being overhauled. For example, Portable Boring Bars, Model Nos. 1162 and 1680, manufactured by Climax Portable Machine Tools, Inc. of Newberg, Oreg., are utilized for on-site boring of such large circular components or work pieces. Generally, such portable boring bars are mounted to the housing of a turbine, the housing of a large valve or the like for proper support and alignment during the boring and/or facing of the work pieces being retained within the housing. If the internal gland seals of a larger turbine diaphragm ring are to be bored, the portable boring bar may, for example, be directly secured to the diaphragm ring during the boring of the internal gland seals.
During the use of such portable boring bars, the work pieces may be maintained in a fixed position with the axes thereof being horizontally disposed within the housing or in a secure location on the floor of the site. For large valves or the like which are disposed vertically, the portable boring bar would be maintained is a fixed position within the housing with the axes thereof extending vertically. The portable boring bars are typically attached to both ends of the housing, diaphragm ring or the like to allow the rotating boring tool means to be advanced through the housing or diaphragm ring for the boring of the interior surfaces of the work pieces. Clearly, in order to accurately bore the work pieces, the portable boring bars must be accurately located with respect to the housing or diaphragm ring. The proper alignment of both Model Nos. 1162 and 1680 of the Portable Boring Bars manufactured by Climax Portable Machine Tools, Inc. requires the proper adjustment of various types of mounting spindles which are employed at each end of the housing or diaphragm ring.
Again, although such portable boring bars have been satisfactorily and successfully employed in the past, there may be certain disadvantages resulting from the manner in which the portable boring bars are mounted. For example, although some facing of annular surfaces on the circular components or work products is possible, because of the manner in which the rotating boring head is mounted to the housing or diaphragm ring, there could be limited access to the ends of the housing and the ends of some of the components mounted therein or to the ends of the diaphragm ring to which the boring machine is secured.
Although such portable boring bars eliminate the need for the circular components to be shipped to a remote location, retaining some of the work pieces within a housing could prevent access to the housing which would otherwise be desirable during the overhauling process. In other words, although a housing may appear to be a convenient means for supporting the portable boring bars in some instances, as a practical matter during the overhauling process of some turbines or the like, it often desirable to have unrestricted access to the housing to perform various other tasks essential during an overhaul of the turbine or the like.
Although there exists a number of permanent vertical boring and/or facing machines and a number of portable boring bars of the type described above, many patents are directed to the more common permanent horizontal boring, facing and/or milling machines. On the other hand, British Patent No. 29,087; Russian Patent No. 751,514; and Russian Patent No. 1,118,488 do disclose machines which might be capable of producing some vertical boring. For example, British Patent No. 29,087 discloses a portable machine which appears to have means for producing horizontal and vertical movement of the tool means which could result in vertical boring or the like. Russian Patent No. 751,514 discloses a device for drilling holes in a cylindrical and conical shell. The drill head tends to extend horizontally but is capable of being moved vertically and even has a feature for providing an inclined angle to the drilling head for the drilling of the tapered portion of the shell. Russian Patent No. 1,118,488 discloses a precision vertical boring and milling machine which has hydrostatic bearings to enable the head stock to be transversed in vertical and horizontal directions through the use of three separate hydraulic circuits.
However, a significant number of patents are directed to various large horizontal boring, facing and/or milling machines which are typically not portable and include rigid mounting means to minimize vibrations or bending which occur during the boring, facing and/or milling process.
British Patent No. 991,286 discloses a horizontal boring and milling machine which has a vertical column which might be capable of limited rotation about the vertical axis but is preferably rigidly secured to a fixed base. The primary features of the machine include various supporting surfaces for movement in a horizontal direction and various slotting and clamping means to insure that the work piece is rigidly maintained in the desired position during the boring and/or milling. British Patent No. 1,297,891 discloses a horizontal jig-boring machine which can be moved in a horizontal direction and includes means for facilitating the horizontal movement on a rigid base for the entire machine.
U.S. Pat. Nos. 2,648,999; 2,674,925; 2,699,694; and 4,632,615 disclose heavy-duty boring, drilling and/or milling machines which are typical in the prior art. Most of these devices bend to product boring in a horizontal direction but do have the capability of producing vertical movement of the boring head. It is significant to note that the machines shown in these patents include rigid means for supporting and moving the boring and/or milling heads in two directions along the horizontal and in a vertical direction. In other words, such machines require rigid supporting means and reliable means for translating the boring and/or milling head in various directions.
While the boring and/or facing machine of the present invention will be seen to be configured different from those generally disclosed hereinabove, it is significant to note that one feature which will assist in the boring and/or facing operation of the preferred machine includes the ability to provide convenient, accurate and reliable positioning of the rotating boring and/or facing component relative to the fixed circular component or work piece. In other words, a significant feature includes the capability of fixedly mounting the circular component or work piece on a support frame while adjusting the boring or facing component to be centrally located relative to the fixed circular component or work piece. Consequently, any means which can be used to produce reliable movement in a horizontal plane in both an X and Y direction is of interest. Clearly, some such features have been provided to some of the machines disclosed in U.S. Pat. Nos. 2,648,999; 2,674,925; 2,699,694; and 4,632,615.
However, a number of other patents disclose specific means for producing accurate and reliable movement within the horizontal plane in X and Y directions which are perpendicular to each other. While such means are of interest, it should be noted that the preferred means for centrally locating the boring and/or facing component of the preferred invention with respect to the fixed circular component or work piece does not require the type of controlled or continuously adjustable movement in the X and Y directions that many components in the prior art may require. Nevertheless, a review of various means for producing movement in the X and Y direction within a horizontal plane may be of interest. For example, U.S. Pat. Nos. 4,189,953; 4,193,317; 4,270,404; 4,341,128; 4,372,223; 4,409,860; 4,628,756; 4,648,723; 4,729,536; 4,972,574; 4,978,233; 5,040,431; and 5,115,354 disclose various means for producing controlled movement of a component within a horizontal plane in both the X and Y directions. However, most of the devices disclosed therein include some form of base support with upwardly disposed rails, guide rods or roller means for the support of an intermediate element to allow the intermediate element to be moved in, for example, the X direction. The intermediate element in turn includes some form of rails, guide rods or roller means for the support of an upper element to facilitate movement of the upper element in the Y direction relative to the intermediate element. Consequently, accurate movement of the upper element is accomplished through the combined movement of the intermediate element with respect to the base support and the upper element with respect to the intermediate element. While all of these devices may present configurations which are satisfactory for the purposes intended, it should be noted that the various rails, guide rods or roller configurations are relatively complicated and may not be desirable for use in such a heavy duty boring and/or facing machine of the present invention.
Specifically, the preferred means for providing the X-Y adjustment of the central boring and/or facing component of the present invention is the subject of a patent application, entitled "An X-Y Movement Mechanism", which was filed on the same date as the present application by the same inventor and has been assigned to the same assignee. Consequently, while the disclosure of the feature for centrally aligning the preferred boring and/or facing component of the preferred machine is disclosed herein, additional alternative configurations are included in the co-pending application filed on the same date as the present application.